JP6111257B2 - Superabsorbent polymer for highly filled or fiber-free hygiene articles - Google Patents

Description

  The present invention relates to an absorbent polymer material particle, a method for producing the absorbent polymer material particle, an absorbent core containing the absorbent polymer material particle, a hygiene article, a method for producing the absorbent core, and an absorbent core obtained by this method Also related.

  Superabsorbents are cross-linked polymers that are water insoluble and can swell and form hydrogels to absorb and retain large amounts of liquid, particularly bodily fluids, preferably urine or blood, under pressure. In general, the absorption of these liquids reaches at least 10 times, or even 100 times, the dry weight of the superabsorbent or superabsorbent composition with water. Thanks to these unique properties, these polymers have applicability primarily in absorbent cores of hygiene articles such as infant diapers, incontinence products, sanitary napkins. A comprehensive overview of superabsorbents and superabsorbent compositions, their use and manufacture is described in Non-Patent Document 1.

German Patent Application Publication No. DE 12 846 International Publication No. WO 2008/155722 International Publication No. WO 2008/155711 International Publication No. WO 2008/155710 International Publication No. WO 2008/155702 International Publication No. WO 2008/155701 International Publication No. WO 2008/155699 European Patent Application Publication No. EP 225 857 International Publication No. WO 01/15647 International Publication No. WO 2011/120504 German patent application DE 2009 049 450 International Publication No. WO 2008/117109 International Publication No. WO 97/11659 European Patent Application Publication No. EP 826 349 International Publication No. WO 98/37846 International Publication No. WO 95/11653 International Publication No. WO 95/11651 International Publication No. WO 95/11652 International Publication No. WO 95/11654 International Publication No. WO 2004/071363 International Publication No. WO 01/89439 German patent application DE 195 29 348 International Publication No. WO 99/34843 International Publication No. WO 2004/037903 European Patent Application Publication No. EP 644 207 US Pat. No. 7,163,966 International Publication No. WO 2010/115671 U.S. Pat. No. 4,286,082 German Patent Application Publication No. 27 06 135 U.S. Pat. No. 4,076,663 German Patent Application No. 35 03 458 German Patent No. 40 20 780 German Patent Application 42 44 548 German Patent Application No. 43 23 001 German Patent Application No. 43 33 056 German Patent Application No. 44 18 818 U.S. Pat. No. 4,340,706 German patent 37 13 601 German Patent No. 28 40 010 International Publication No. WO 96/05234

"Modern superabsorbent polymer technology" L. Buchholz, A.B. T. T. Graham (editor) Wiley VCH published in 1998

  Superabsorbents are made by free polymerization of monomers that are acid functional, usually partially neutralized in the presence of a crosslinker. By varying the polymerization conditions and processing conditions of the monomer composition, the crosslinking agent and also the hydrogel obtained after polymerization, polymers having different absorption characteristics can be made. Another possibility is presented by the production of graft polymers, for example by using processed starch, cellulose and polyvinyl alcohol, as described in US Pat.

  The current trend in diaper construction is to produce always thinner absorbent cores with reduced cellulose fiber content and increased high absorbent content, among others. The strength of the thinner structure not only increases the comfort of wearing, but also reduces the cost of packaging and stockpiling. For example, the latest generation of absorbent cores as described in US Pat. Nos. 5,037,028 and 2020 are essentially cellulose-free (and hence this type of diaper is also called fluffless diapers). In absorbent cores containing cellulose, the stiffening of superabsorbent particles achieved by cellulose, for example, in the latest generation of absorbent cores, thermoplastic fibers stiffen superabsorbent particles on a surface substrate. Can be achieved.

  Thinner diaper structures and the tendency of temporary liquid containment and loss of cellulose fiber conduction function have led to distinctly different changes in the required performance profile of superabsorbents. Of obvious importance here is the ability of the hydrogel to directly prevent urine leakage during urination. This is accomplished by the superabsorbent / hydrogel properties. Thereby, the liquid is sufficiently absorbed and dispersed in the gel layer. During inflation, on the one hand, the amount of uncoagulated urine in the diaper is simultaneously minimized. Suitable superabsorbents also have good transport properties, thus ensuring optimal utilization of the entire hygiene article.

  However, prior art superabsorbents are not well suited for use in the new generation cellulose-free diaper structures described above.

  The problem addressed by the present invention is therefore the problem of overcoming the disadvantages associated with the superabsorbents associated with the prior art.

  More specifically, the problem addressed by the present invention is a high absorption which is very advantageous for use in absorbent cores with low cellulose fiber content, eg cellulose free structures as described in US Pat. It is a problem of providing an agent.

  Another problem addressed by the present invention is that those superabsorbents that can be reliably used in a cellulose-free structure as described, for example, in US Pat. It is a problem to provide a selection process of selecting from.

Absorbent polymer material particles having at least one of the following properties contribute to the solution of the problem first identified.
1) For at least one numerical value i selected from integers from 2 to 12, the maximum APC _{i × 10 sec} value (= APC _max value) is 1.6 or more, preferably 2.0 or more, More preferably, it is 2.4 or more, and the APC _max value is preferably 14.0, more preferably 12.0, and most preferably 10.0.
2) For all values i in integers from 2 to 12, the sum of all APC _{i × 10 sec} values (= APC _SUM ) is 12 or more, preferably 18 or more, and more The APC _SUM value is preferably 55, more preferably 50, and most preferably 45.

The APC _{i × 10 sec} value is defined as follows.

APC _{i x 10 sec} = QI _{i x 10 sec} value ² x PI _{i x 10 sec} value where
The QI _{i × 10 sec} value is the numerical value of the swelling index measured by the test method described herein i × 10 sec after addition of a 0.9% NaCl solution by weight,
-PI _{i x 10 sec} value is i x 10 after adding NaCl solution with a weight concentration of 0.9%.
Let the penetration index measured by the test method described herein after 2 seconds.

  In particular examples of absorbent polymer material particles of the present invention, these absorbent polymer material particles are preferably 22 g / g or more, preferably WSP 241.3 (testing method of global strategic partners EDANA and INDA). Has a centrifuge retention capacity (CRC) of 24 g / g or more, more preferably 26 g / g or more, and most preferably 28 g / g or more.

  In another specific embodiment of the absorbent polymer material particles of the present invention, these absorbent polymer material particles are WSP 242.3 and are at least 16 g / g, preferably at least 18 g / g, more preferably at 20 g / g. g, and most preferably 22 g / g or more, having an absorption under pressure (AUP) of 0.7 psi.

  Desirable absorbent polymer material particles in the present invention are fibers, foams or particles, among which fibers and particles are preferred, and particles are most preferred.

  The polymer fibers desirable in the present invention are dimensioned so that they can be included in the yarn for the fabric or as a yarn and also directly in the fabric. According to the invention, the polymer fibers have a length in the range of 1 to 500 mm, preferably 2 to 500 mm, and more preferably 5 to 100 mm, 1 to 200 denier, preferably 3 to 100 denier, More preferably, the diameter is in the range of 5 to 60 denier.

  Desirable absorbent polymer material particles in the present invention are sized so that they have an average particle size in the range of 10 to 3000 μm, preferably 20 to 3000 μm, and more preferably 150 to 850 μm with WSP 220.2. It is decided. Here, the proportion of polymer particles having a particle size in the range of 300 to 600 μm is 50% by weight or more, more preferably 65% by weight or more, and most preferably 80% by weight, based on the total weight of the absorbent polymer particles. Reaching the above is particularly suitable.

  According to the present invention, it is further preferable that the absorbent polymer material particles in the present invention are based on a partially neutralized crosslinked acrylic acid. In this connection, the absorbent polymer material particles in the present invention are crosslinked polyacrylate having a microporous structure, and the crosslinked polyacrylate is all 50% by mass or more based on the mass of the polymer material. It is very preferable to be composed of a monomer having a carboxylate group in an amount of preferably 70% by mass or more, and more preferably about 90% by mass or more. According to the present invention, the absorbent polymer material particles in the present invention are neutralized by the mass of the polymer material, preferably 20 mol% or more, more preferably 50 mol% or more, and even more preferably 60 to 85 mol%. More preferably, the base is based on about 50% by mass or more, preferably about 70% by mass or more based on both of the polymerized acrylic acid.

The absorbent polymer material particles in the present invention are preferably obtained by a process including the following steps.
1) a polymerizable monoethylenically unsaturated acid functional monomer (α1) or a salt thereof, optionally a monoethylenically unsaturated monomer (α2) polymerizable with the monomer (α1), a blowing agent (α3), and And a step of free-polymerizing an aqueous monomer solution containing at least one crosslinking agent (α4) for obtaining a hydrogel having a microporous structure.
2) optionally crushing the hydrogel having a microporous structure.
3) A step of drying the hydrogel having a microporous structure, optionally pulverized, in order to obtain absorbent polymer material particles having a microporous structure.
4) A step of optionally crushing and sieving the resulting absorbent polymer material particles having a microporous structure.
5) A step of subjecting the resulting absorbent polymer material particles having a microporous structure to post-crosslinking on the surface together with a crosslinking agent having two or more functional groups capable of reacting with the acidic groups on the surface of the polymer material. . Before the post-crosslinking, during the post-crosslinking or after the post-crosslinking, the surface of the polymer material comes into contact with the aluminum salt. In step 1), first, a polymerizable monoethylenically unsaturated acid is obtained to obtain a polymer gel. A functional monomer (α1) or a salt thereof, optionally a monoethylenically unsaturated monomer (α2) polymerizable with the monomer (α1), a foaming agent (α3), and also a hydrogel having a microporous structure is obtained. A monomer aqueous solution containing at least one crosslinking agent (α4) for free polymerization. The monoethylenically unsaturated acid functional monomer (α1) may be partially or completely, preferably partially neutralized. Preferably, the monoethylenically unsaturated acid functional monomer (α1) is in a neutralized state of 25 mol% or more, more preferably 50 mol% or more, and even more preferably about 50 to 80 mol%. The disclosure of U.S. Pat. No. 6,057,086 is hereby incorporated herein by reference in this regard. A neutralization reaction may also be brought about partially or completely after polymerization. The neutralization reaction may be effected using alkali metal hydroxides, alkaline earth metal hydroxides, ammonia, and also carbonates and bicarbonates. Any other base that can be combined with an acid to form a water soluble salt is also contemplated. Neutralization reactions mixed with different bases are also conceivable. Preference is given to a neutralization reaction of a mixture of carbonate and / or bicarbonate (also acting as a blowing agent) and alkali metal hydroxide, more preferably a mixture of sodium carbonate and sodium hydroxide.

  Furthermore, in the inventive water-absorbing polymer structure, free acid groups may dominate, as this polymer structure exhibits acidic pH. This acidic water-absorbing polymer structure may be at least partially neutralized by a polymer structure having a free basic group, preferably an amine group, the amine group being basic compared to the acidic polymer structure. These polymer structures are referred to in the literature as “mixed bed ion-exchangeable absorbent polymers” (MBIEA polymers) and are disclosed, inter alia, in US Pat. The disclosure of U.S. Pat. No. 6,057,834 is hereby incorporated by reference and thus forms part of the present disclosure. In general, the MBIEA polymer constitutes a composition having a basic polymer structure capable of anion exchange first and an acidic polymer structure compared to the basic polymer structure capable of cation exchange second. The basic polymer structure is mainly obtained by polymerization of a monomer having a basic group and having a basic group or a group that can be converted into a basic group. These monomers are primarily primary, secondary, or tertiary amines, or the corresponding phosphines, or monomers having at least two of the above functional groups. Monomers of this group include ethyleneamine, allylamine, diallylamine, 4-aminobutene, alkyloxycycline, vinylformamide, 5-aminopentene, carbodiimide, formaldacine, melamine, etc., and their secondary or primary Includes tertiary amine derivatives.

  The monoethylenically unsaturated monomer (α1) containing a desirable acidic group is preferably a compound specified in Patent Document 24 as a monoethylenically unsaturated monomer (α1). U.S. Patent No. 6,057,096 is hereby incorporated herein by reference and is therefore part of the present disclosure. A particularly desirable monoethylenically unsaturated monomer (α1) containing an acidic group is acrylic acid or methacrylic acid, and acrylic acid is most desirable.

  Acrylamide, methacrylamide, or vinylamide may be used as the monoethylenically unsaturated monomer (α2) copolymerizable with the monomer (α1). A desirable comonomer is a comonomer containing the monomer (α1), and is preferably a compound described in Patent Document 24 as a comonomer (α2).

  A copolymerizable, monoethylenically unsaturated surfactant is used as a comonomer (α2) in a special embodiment of the method for producing water-absorbing polymer material particles of the present invention. These special surfactants have polymerizable functional groups.

Preferably, the chemical structure of these surfactants is

R ¹ and R ² are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, n-pentyl, 2-methylbutyl, 2,2-dimethylpropyl, hydroxyl group, acetyl or allyl, and n is 2 to 20, m is assumed to take 2 to 20. EO and PO are hydrophilic and hydrophobic blocks, respectively, to create surfactant properties. Reactive allyl groups are desirable for R1 or R2 in accordance with the present invention because they are later copolymerized as acryloyl groups and are stable upon hydrolysis. The product Pulluriol® A23R from BASF Corporation (currently BASF Europe) is mentioned as an example of such a copolymerizable surfactant.

Useful blowing agents (α3) include in particular any co-additive known to those skilled in the art. Such co-additives are advantageous during polymerization for the formation of spaces such as pores and hence for the formation of microporous structures within the polymer gel. Useful blowing agents include, in particular, blowing agents disclosed as suitable blowing agents in, for example, US Pat. In particular, carbonate-based blowing agents are discussed herein. When heated, the blowing agent in a dissolved or dispersed state in the monomer solution containing carbonate releases carbon dioxide. The blowing agent may be any carbonate or bicarbonate containing salt, or a mixed salt. And carbon dioxide as a gas, or solid materials sodium carbonate, potassium carbonate, ammonium carbonate, magnesium carbonate, magnesium hydroxide carbonate, calcium carbonate, barium carbonate, bicarbonate, and hydrates thereof, or It may contain naturally occurring carbonates such as other cations, dolomite and mixtures thereof. Preferred carbonate blowing agents are MgCO ₃ , (NH ₄ ) ₂ CO ₃ and mixtures thereof. In this connection, it is more preferred to add from about 0.05% to about 5.0% by weight of blowing agent, based on the weight of the optionally partially neutralized monomer (α1), more Preferably based on optionally partially neutralized acrylic acid. It is most preferred to add from about 0.2% to about 3.0% by weight blowing agent. The blowing agent may also be encapsulated, for example as described in US Pat.

In addition to the foaming agent described above or in place of the foaming agent described above, a hollow body having a shell of an organic material or an inorganic material is also used to form a space in the polymer material as described in US Pat. Therefore, it may be added to the monomer solution. The hollow body having an organic material shell is a hollow body selected from the following group.
A hollow body having a shell of a polymeric thermoplastic material;
A hollow body having a shell of a polymeric non-thermoplastic material;

In general, useful hollow bodies include:
-Gas-filled microballoons based on thermoplastic or non-thermoplastic polymers;
-Polyelectrolyte multi-layer capsules,
-Hollow spheres based on thermoplastic or non-thermoplastic polymers;
A microsphere particle based on a thermoplastic polymer, for example available under the brand name EXPANCEL®, or
A hollow body having a shell of polycrystalline aluminum oxide;

  Useful cross-linking agents (α4) preferably also include the compounds identified in Patent Document 24 as cross-linking agents (α3). Is this enumeration related to US Pat. If not, (α4) will be correct. Among these crosslinking agents, water-soluble crosslinking agents are particularly suitable. Most preferred is N, N'-methylenebisacrylamide, polyethylene glycol di (meth) acrylate, triallylmethylammonium chloride, tetraallylammonium chloride, and allyl nonaethylene glycol formulated in 9 mol of ethylene oxide per mol of acrylic acid. Acrylate.

  The monomer solution also contains a water-soluble polymer (α5) in addition to the monomer (α1) and optionally (α2), the blowing agent (α3), and also at least one crosslinking agent (α4). It may be. Desirable water-soluble polymers are partially or wholly hydrolyzed polyvinyl alcohol, polyvinyl pyrrolidone, starch or starch derivatives, polyglycol or polyglycolic acid. The molecular weight of these polymers is not critical if they are water soluble. Desirable water-soluble polymers are starch or starch derivatives or polyvinyl alcohol. The water-soluble polymer, preferably a synthetic water-soluble polymer such as polyvinyl alcohol, does not only function as a bonding base for the monomers to be polymerized. It is also conceivable to mix these water-soluble polymers into the polymer gel only after polymerization or into the already dried water-absorbing polymer gel.

  In addition, the monomer solution may also contain additives (α6), such as EDTA (ethylenediaminetetraacetic acid). Such additives include initiators or complexing agents that may be required for polymerization in particular.

  Useful solvents for the monomer solution include water, organic solvents, or a mixture of water and organic solvents, the choice of which depends in particular also on the polymerization process.

The relative amounts of the monomers (α1) and (α2), the foaming agent (α3), the cross-linking agent (α4), the water-soluble polymer (α5), and the additive (α6) in the monomer solution are as follows: In step 3), the absorbent polymer material particles having a microporous structure obtained after drying are preferably selected so as to comply with the following criteria.
The monomer (α1) is about 20 to 99.999% by weight, preferably about 55 to 99.99% by weight, and more preferably about 70 to 98.79% by weight;
The monomer (α2) is about 0 to 80% by mass, preferably about 0 to 44.99% by mass, and more preferably about 0.1 to 44.89% by mass;
The cross-linking agent (α4) is about 0 to 5% by mass, preferably about 0.001 to 3% by mass, and more preferably about 0.01 to 2.5% by mass;
The water-soluble polymer (α5) is about 0 to 30% by weight, preferably about 0 to 5% by weight, and more preferably about 0.1 to 5% by weight;
The additive (α6) is about 0 to 20% by weight, preferably about 0 to 10% by weight, and more preferably about 0.1 to 8% by weight; and
The water (α7) is about 0.5 to 25% by weight, preferably about 1 to 10% by weight, and more preferably about 3 to 7% by weight;
The total mass of (α1) to (α7) is 100%.

  Optimum values regarding the concentrations of the monomer, the foaming agent, the cross-linking agent, and the water-soluble polymer in the monomer solution are determined by a simple prior test, or the prior art, particularly Patent Documents 28- Inferred from 36 publications. For the free polymerization of the monomer solution, useful polymerization processes are in principle all polymerization processes known to those skilled in the art. For example, mention should be made of solution polymerization which preferably occurs continuously in a kneading reactor such as an injection molding machine or during spray polymerization, reverse phase emulsion polymerization and reverse phase suspension polymerization.

  Solution polymerization is preferably carried out in water as a solvent. Solution polymerization may be performed continuously or discontinuously. The prior art discloses a wide range of possible changes with respect to temperature, initiator type and amount, and reaction conditions such as reaction solution. Standard processes are described in US Pat. Those disclosures are hereby incorporated herein by reference and therefore form part of this disclosure.

  As is generally customary, polymerization is caused by initiators. As initiators for initiating polymerization, all initiators that form free radicals under polymerization conditions and are commonly used in the production of superabsorbents are possible. It is also possible to initiate the polymerization by irradiating the polymerizable aqueous mixture with an electron beam. On the other hand, the polymerization may also be triggered by irradiation of high energy radiation in the presence of a photoinitiator without an initiator of the type described above. The polymerization initiator may be present dissolved or dispersed in the monomer solution. Useful initiators include all compounds that break down to free radicals and are known to those skilled in the art. These include in particular the initiators already described as possible initiators in the patent document 24. Particularly preferably, a water-absorbing polymer is likely to be produced using a redox system comprising hydrogen peroxide, sodium peroxodisulfate and ascorbic acid.

  Reverse phase suspension and emulsion polymerization may also be used to produce the absorbent polymer material particles of the present invention. In these processes, the monomer (α1), the foaming agent (α3), the other monomer (α2) optionally contained therein, the water-soluble polymer (α5), and the additive A partially neutralized aqueous solution of (α6) is dispersed with the aid of protective colloids and / or emulsifiers in a hydrophobic organic solvent. Polymerization is then initiated using a free initiator. The crosslinking agent (α4) is either dissolved in the monomer solution and measured together with the monomer solution, or is optionally added alone during polymerization. Optionally, a water-soluble polymer (α5) is added as a graft base for the monomer solution or by directly entering the oil phase. Thereafter, moisture is removed from the mixture as an azeotrope and the polymer is filtered.

  Furthermore, both in the case of solution polymerization and in the case of reversed-phase suspension and emulsion polymerization, the crosslinking is carried out by polymerization of the polyfunctional crosslinking agent (α4) dissolved in the monomer solution and / or during the polymerization step. It can be achieved by reaction of a suitable crosslinking agent with the functional group of the polymer. The process is described, for example, in US Pat.

  In step 2), the hydrogel having a microporous structure obtained in step 1) is optionally crushed. This pulverization affects in particular when the polymerization is carried out using solution polymerization. Grinding may be performed using a grinding apparatus known to those skilled in the art, such as a meat grinder.

  In step 3), said hydrogel having a microporous structure, optionally pre-ground, is dried. The hydrogel is preferably dried in a suitable dryer or oven. Illustrative examples include a rotating tube oven, a fluidized bed dryer, a pan-type dryer, a paddle dryer, or an infrared dryer. According to the invention, in step 3) the hydrogel is brought to a drying temperature mainly in the range from 100 to 200 ° C. and a moisture content of 0.5 to 25% by weight, preferably 1 to 10% by weight. Drying is more preferable.

  In step 4), when the absorbent polymer material particles having a microporous structure obtained in step 3) are the absorbent polymer material particles obtained by solution polymerization, the first specified request is obtained. May be crushed and screened to a particle size to be achieved. The absorbent polymer material having a dry microporous structure is suitably crushed with a suitable mechanical grinding device, for example a ball mill, and sifting is carried out at the same time, for example using a screen with a suitable mesh size. Also good.

  In step 5), the absorbent polymer material particles having a microporous structure, optionally crushed and screened, have two or more functional groups capable of reacting with the acidic groups on the surface of the polymer material. The surface of the polymer material is contacted with an aluminum salt, preferably aluminum lactate and / or aluminum sulfate before, during or after post-crosslinking, and the surface of the polymer material is post-crosslinked with a crosslinking agent. To do.

  For the post-crosslinking of the surface, the absorbent polymer material particles having a microporous structure, which has been dried, optionally crushed and screened, after finishing step 3) or step 4), or step 2) The finished, undried but already suitably ground hydrogel with microporous structure is contacted with a suitable organic or chemical surface postcrosslinker. In particular, when the post-crosslinking agent is not a liquid under the conditions at the time of post-crosslinking, the post-crosslinking agent is preferably in the form of a liquid containing the absorbent polymer material particles or the post-crosslinking agent and a solvent. In contact with the polymer gel. The solvent used is preferably water, a water-miscible solvent such as methanol, ethanol, 1-propanol, 2-propanol, or 1-butanol, or a mixture of two or more of these solvents. And water is the most preferred solvent. The post-crosslinking agent is present in the liquid in an amount in the range of 5 to 75% by weight, preferably 10 to 50% by weight, most preferably 10 to 40% by weight, based on the total weight of the liquid. It is more suitable to do.

  The contact of the absorbent polymer material particles having a microporous structure or the optionally pulverized polymer gel having a microporous structure with the liquid containing the post-crosslinking agent is preferably This is achieved by mixing the liquid with the polymer material or the polymer gel.

  Suitable mixing units for adding the liquid include, for example, Patterson Kelly mixer, Dreis (R) turbulent mixer, Redige mixer, Ruberg mixer, screw mixer, pan mixer, fluid bed mixer, and also polymer There is a continuous vertical mixer (Shugi mixer) where the raw materials are mixed at high frequency using a rotating blade.

  The absorbent polymer material particles or hydrogel having a microporous structure is preferably 20% by mass or less, more preferably 15% by mass or less, further preferably 10% by mass or less, and further more preferable at the time of post-crosslinking. In contact with 5% by weight or less of solvent, preferably water.

  In the case of a polymer material in the form of a suitable spherical particle, according to the invention, only the outer region, not the inner region of the polymer material particle, is in contact with the liquid and thus with the post-crosslinking agent, Is preferred.

A post-crosslinking agent is preferably understood as a compound having two or more functional groups capable of reacting with acidic groups on the surface of the polymer material during a condensation reaction (= condensation crosslinking), addition reaction or ring-opening reaction. The Preferably, the post-crosslinking agent is a cross-linking agent specified in Patent Document 24 as a cross-linking agent for cross-linking agent 2. Among these compounds, particularly preferred crosslinking agents are condensation crosslinking agents such as diethylene glycol, triethylene glycol, polyethylene glycol, glycerol, polyglycerol, propylene glycol, diethanolamine, triethanolamine, polyoxypropylene, oxyethylene-oxy Propylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, trimethylolpropane, pentaerythritol, polyvinyl alcohol, sorbitol, 1,3-dioxolan-2-one (ethylene carbonate), 4-methyl-1,3-dioxolane -2-one (propylene carbonate), 4,5-dimethyl-1,3-dioxolan-2-one, 4,4-dimethyl-1,3-dioxolan-2-one, 4- Til-1,3-dioxolan-2-one, 4-hydroxymethyl-1,3-dioxolan-2-one, 1,3-dioxan-2-one, 4-methyl-1,3-dioxane-2- On, 4,6-dimethyl-1,3-dioxan-2-one, and 1,3-dioxolan-2-one.

  Once the absorbent polymer material particles having a microporous structure or the hydrogel having a microporous structure are contacted with the cross-linking agent or a liquid containing the cross-linking agent, preferably, as a result, They are 50-300 ° C. so that the outer regions of the polymer material particles are more strongly cross-linked compared to the inner region (= cross-linked) and are also dried at the same time if a hydrogel is used. , Preferably 75 to 275 ° C, more preferably 150 to 250 ° C. The duration of the heat treatment is limited by the risk that the desired polymer material property profile will be lost by the action of heat.

  Before the post-crosslinking step, during the post-crosslinking step, or after the post-crosslinking step, the surface of the polymer material having a microporous structure or the hydrogel is in contact with an aluminum salt, preferably aluminum lactate. . Contacting an aqueous solution containing the cross-linking agent and also the aluminum salt, preferably aluminum lactate, with the absorbent polymer material particles having a microporous structure or the hydrogel having a microporous structure; It is particularly preferred that the treatment with the aluminum salt is carried out simultaneously with the step of post-crosslinking the surface by heating.

Suitable aluminum salts are in particular AlCl ₃ × 6H ₂ O, NaAl (SO ₄ ) ₂ × 12H ₂ O, KAl (SO ₄ ) ₂ × 12H ₂ O, or Al ₂ (SO ₄ ) ₂ × 14 to 18H _2. O, aluminum lactate, or a water-insoluble aluminum compound such as aluminum oxide, for example Al ₂ O ₃ or aluminate. It is particularly preferred to use aluminum lactate, aluminum sulfate or a mixture of aluminum lactate and aluminum sulfate.

  The solution of the problem specified at the beginning includes an upper substrate layer, a lower substrate layer, and an absorbent layer disposed between the upper substrate layer and the lower substrate layer, the absorbent layer of the present invention. An absorbent core containing raw material particles and less than 0.1 g, particularly preferably less than 0.05 g, most preferably less than 0.01 g of cellulose fibers per gram of absorbent polymer material particles also contributes. .

  An “absorbent core” for the purposes of the present invention is said to be absorbent particles, for example diapers, said impervious upper layer facing away from the wearer's body and liquid permeable wearer. Is preferably understood to mean a structure that can be arranged between the lower layer facing the body side of the body and the main function of the structure is the liquid, for example blood or urine absorbed by the absorbent particles To absorb and store. The absorbent core itself preferably does not comprise an absorbent system of the absorbent particles, an upper layer, or a lower layer.

  However, it is most preferable in the present invention that basically no cellulose fiber is used in the absorbent particles. In the present specification, particles, for example, containing 10% by mass or less of cellulose fiber, 5% by mass or less of cellulose fiber, 1% by mass or less of cellulose fiber, or not containing cellulose fiber, or at most are sufficient. The term “basically no cellulose fibers” is used to indicate an absorbent core that contains no amount of cellulose fibers. This type of core is specifically described in US Pat.

  In a preferred embodiment of the absorbent core of the present invention, the absorbent core includes a thermoplastic material and various chambers containing the absorbent polymer material particles. In this context in the present invention, particularly suitable absorbent cores are referred to and described as absorbent cores in US Pat. As a result, in a particularly preferred embodiment of the present invention, the absorbent core comprises a layer of thermoplastic material and various chambers containing the absorbent polymer material particles, the chamber being Each is surrounded by an upper or lower substrate layer and also by a thermoplastic material. In accordance with the teachings of the above patent application, a specific substrate (upper part) in the particle mass is formed to form a grid pattern that forms each land area and each junction area between each land area. Alternatively, such a structure can be realized by applying the absorbent polymer material particles to the lower substrate layer). The “land area” is an area where the thermoplastic material does not come into direct contact with the upper or lower base material layer. The “joining area” is an area where the thermoplastic material is in direct contact with the upper or lower base material layer. The joining area of the grid pattern contains little or no absorbent polymer material particles. The land area and the joint area may have a number of external shapes including, but not limited to, a circle, an ellipse, a square, a rectangle, a triangle, and the like.

An example of the absorbent core in the present invention is a core including a first sublayer and a second sublayer adjacent to the first sublayer,
The first sub-layer also includes a chamber containing the absorbent polymer material particles surrounded by the upper substrate layer and the upper substrate layer and a first layer of thermoplastic material;
The second sublayer also includes a chamber containing the absorbent polymer material particles surrounded by the lower substrate layer and the lower substrate layer and a second layer of thermoplastic material;
The first layer of thermoplastic material is adjacent to the second layer of thermoplastic material. This structure corresponds to the structure shown in FIGS. 7A and 7B of cited document 2 as an example.

  The thermoplastic material of the preferred design of the absorbent core in the present invention serves mainly to cover and at least partially fix the absorbent polymer material particles in contact with the upper or lower substrate layer. . In one embodiment of the present invention, the thermoplastic material may be in an essentially uniform arrangement within the absorbent polymer material particles between the polymers. However, in certain embodiments, for example, as shown in FIGS. 3 and 4 of reference 2, the thermoplastic material is at least partially in contact with the absorbent polymer material particles and is partially The fiber layer may be in contact with the upper or lower substrate layer. In this case, the layer of thermoplastic material may be available, for example, by melting a fibrous thermoplastic material.

  Suitable materials for the upper or lower substrate layer and also for the thermoplastic material are, for example, the materials described as “Suitable materials for these chemical components” in cited document 2.

  The method for producing this type of absorbent core preferably corresponds to the method described in cited document 7 as an example.

As a result, the process includes the following steps.
A first pattern for forming a first absorbent layer such that the absorbent polymer material particles have a discontinuous distribution on the lower substrate layer, the absorbent on the lower substrate layer; Placing polymer material particles;
A second pattern for forming a second absorbent layer such that the absorbent polymer material particles have a discontinuous distribution on the upper substrate layer, the absorbent on the upper substrate layer; Placing polymer material particles;
-Placing a layer of thermoplastic material on the absorbent polymer material particles and the lower and upper substrate layers to cover the absorbent polymer material particles on the lower and upper substrate layers;
And
-Linking the first and second absorbent layers such that at least one of the thermoplastic material of the first absorbent layer is in contact with at least one of the thermoplastic material of the second absorbent layer; Step.

  A hygiene article comprising the absorbent core of the present invention also contributes to the solution of the problems specified at the outset, which hygiene article is preferably a diaper. The diaper mainly consists of a liquid permeable lower layer (facing the diaper wearer's body side when the diaper is worn) and the side away from the diaper wearer's body when the diaper is worn. Including an upper layer that is essentially impermeable to liquid) and also the absorbent core of the present invention, the absorbent core being disposed between the lower layer and the upper layer. In addition to these three components, the sanitary article is described in another component, for example, the resealable locking system described in reference 7 as an example, or in reference 2 as an example. It may include another acquisition layer that is confined between the lower layer that is permeable to liquid and the absorbent core of the present invention. A suitable diaper structure in the present invention is shown in FIG.

The solution of the problem specified at the beginning also includes a process for producing an absorbent core comprising an upper substrate layer, a lower substrate layer, and also an absorbent layer disposed between the upper and lower substrate layers. Also contributing, the absorbent layer comprises the absorbent polymer material particles and less than 0.1 g cellulose fiber per gram of absorbent polymer material particles, the manufacturing process comprising the following steps.
A) A step of preparing the absorbent polymer material particles of the present invention.
B) Incorporating the absorbent polymer material particles into the absorbent core.

The step of incorporating the raw material particles into the absorbent core includes the following steps, for example.
B1) In the first pattern for forming the first absorbent layer so that the absorbent polymer material particles have a discontinuous distribution on the lower base material layer, the absorption on the lower base material layer Placing the conductive polymer material particles.
B2) In the second pattern for forming the second absorbent layer so that the absorbent polymer material particles have a discontinuous distribution on the upper base material layer, the absorption on the upper base material layer Placing the conductive polymer material particles.
B3) Disposing a layer of thermoplastic material on the absorbent polymer material particles and the lower and upper substrate layers to cover the absorbent polymer material particles on the lower and upper substrate layers.
And
B4) The first and second absorbent layers are arranged so that at least one place of the thermoplastic material of the first absorbent layer is in contact with at least one place of the thermoplastic material of the second absorbent layer. The connecting step.

The solution of the problem specified at the beginning also includes a process for producing an absorbent core comprising an upper substrate layer, a lower substrate layer, and also an absorbent layer disposed between the upper and lower substrate layers. Also contributing, the absorbent layer comprises the absorbent polymer material particles and less than 0.1 g cellulose fiber per gram of absorbent polymer material particles, the manufacturing process comprising the following steps:
a) Appropriate absorbency based on the measurement results of the square of the swelling index and the permeability index (= APC value) of the product at least one time t ₁ after the liquid is applied to the absorbent polymer structured particles Selecting polymer material particles;
b) incorporating the absorbent polymer material particles thus selected into the absorbent core.
And the suitable structure of an absorptive core is a structure already described as suitable first in relation to the said absorptive core of this invention.

In one preferred embodiment of the process according to the invention, step a) comprises measuring the square of the product swelling index and the permeability index (= APC value) at at least 11 different times t _i , Selecting the absorbent polymer material particles based on the sum of all the APC values obtained.

  The absorbent core obtained by the process described above also contributes to the solution of the problem specified at the outset.

  The invention will now be described in more detail with the aid of drawings, test methods and non-limiting examples.

The measuring pot 6 used for measuring the APC value together with the particle size ([mm]) is shown. Fig. 2 shows a plunger 7 inserted into the measuring pot 6 shown in Fig. 1 used for measuring the APC value together with the particle size ([mm]). A PVC lid 8 for the measuring pot 6 is shown. A weight 10 placed on the plunger 7 is shown. The height and width of the weight 10 depends on the weight of the material used. The total load of the plunger 7 and the weight 10 is 594 g ± 5 g (corresponding to a load of 21 g / cm ² ± 0.2 g / cm ² ). The experimental apparatus included in the measurement of APC value is shown.

Test Method Measurement of APC Value The APC value is measured using the measuring device shown in FIG.

1. Principle of Measurement In order to measure the APC value, 1.800 g (± 0.005 g) of the absorbent polymer material particle to be analyzed (hereinafter referred to as “SAP”) is a mesh as a base shown in FIG. It is swung into the measuring pot 6 having a screen and is evenly distributed on the screen base. The plunger shown in FIG. 2 is then inserted into the measurement pot and, as shown in FIG. 5, 21.0 g / cm ² ± 0.2 g / cm ² (the total load of the plunger and weight is 594 g ± 5 g). ) Such that the pressure is applied to the SAP material. As shown in FIG. 5, the cylinder unit (measurement pot 6, SAP, plunger 7 and weight 10) is installed on a support base 15 having a circular notch. The support 15 is on the scale 1. The peristaltic pump 11 sends the test solution to the cylinder unit at a constant flow rate. It is continuously measured in the collection container 13 under the support 15 (on the scale 1). The measurement pot 6 has outlets A and B at a predetermined height (as shown in FIG. 5, the lower outlet B of the measurement pot 6 shown in FIG. Closed.) As the gel layer occurs, a liquid column can be established up to the height of the outlet A. Accordingly, excess liquid exits through the outlet A. This liquid passes through a single tube 16 about 10 cm long, flows into the collection container 14 and is continuously measured on the balance 2. Throughout the entire measurement, the growth of the gel layer is measured continuously as well. All measurements (balance, height measurement) are automatically captured and stored.

If the measurement conditions (total SAP measurement [g], pressure acting on SAP [g / cm ² ], flow rate of test solution to cylinder unit [g / sec]) are selected to be constant, the following measurements Data (σ1) to (σ3) are continuously captured as a result.
(Σ1) Change in height of the growing gel layer by the height measuring device 3.
(Σ2) Change in weight on the left balance 1 in FIG. 5 due to the test solution passing through the gel layer.
(Σ3) Change in weight on the right balance 2 in FIG. 5 due to the test solution exiting via the outlet A.

2. Measuring device used-two scales (1,2) with a PC interface with a minimum accuracy of 0.1 g (eg CP8201 from Sartorius).
A height measuring device 3 (for example, Digico 2 manufactured by Tessa Co.) having a PC interface with a minimum precision of 0.1 mm and a minimum measurement length of 30 mm.
-Liquid storage container 4 (corresponding to a predetermined amount of liquid at least according to the test parameters, for example 30 minutes = 3600 g at 2 g / s).
-Test device-Device 5 and load (see also Figs. 1 and 2)
As shown in FIG. 1, a transparent measuring pot 6 (d1 (inner diameter) = 60.3 mm ± 0 mm, h = 100 mm ± 0.5 mm) and h1 ^* = 55 mm and h2 ^* = 83 mm made of Plexiglas® Two outlets (the upper outlet is used and the lower outlet is closed during the measurement) (inner diameter = 10 mm) ( ^* means the height of each outlet). The bottom side of the measuring pot is equipped with a stainless steel mesh screen (400 mesh = 36 μm).
-PVC plastic plunger 7 (d2 (inner diameter) = 60 mm ± 0 mm) (d1-d2 = 0.3 mm and h = 150 mm) as shown in FIG. The bottom side of the plastic plunger 7 is provided with a stainless steel mesh screen (400 mesh = 36 μm). The height of the bottom of the plastic plunger 7 is 28 mm. There are four pillars at the bottom, which contribute to the stabilization of the mesh screen. Each strut is provided with a passageway in the lower region (i.e., the region in contact with the mesh screen) of approximately 3 x 5.5 mm to ensure a uniform distribution of liquid.
A close lid 8 having a notch for the plastic plunger 7 and a liquid feed pipe 9 (see FIG. 3);
A weight 10 (see FIG. 4) installed on the plastic plunger 7; The plastic plunger 7 and the weight 10 as a whole must satisfy a specified weight. The standard herein is a total mass of 594 g ± 5 g (corresponding to a pressure of 21.0 g / cm ² ± 0.2 g / cm ² , which corresponds to a pressure of about 0.3 psi).
A liquid pump 11 (for example, a peristaltic pump) having a capacity of 30 mL / min to 400 mL / min, for example, SB-2V pump head and Tygon® standard tube (inner diameter 4.8, tube thickness 1. 6. External shape 8.0) MCP standard made by Ismatech.
-A computer system with suitable software for recording the scale display and height measurement.
-Collection containers 13 and 14 for liquids (minimum 3.6 L).
A support 15 having a circular notch (diameter 6 cm, exactly corresponding to the width of the mesh screen in the measuring pot). This notch is centered on a plastic ring (diameter 7.2 cm, roughly equivalent to the outer shape of the measuring pot) with a height of about 2 cm (during measurement, liquid can pass unimpeded and the height measurement is always Enclosed with the cylinder unit as done in the same place.

3. Performing a measurement At least one double decision should be made.

preparation work:
The liquid reservoir 4 is filled so that sufficient test liquid (0.9% NaCl solution) can be supplied. The temperature of the test solution is 23 ° C. ± 2.0 ° C. (room temperature = 23 ° C. ± 2.0 ° C., and the humidity at the temperature is 55% ± 15%).
The peristaltic pump 11 is adjusted according to the desired flow rate; To this end, to the extent that appropriate, the system can be used to record measurements, or alternatively can be used to record the required amount determined using a stopwatch and a glass beaker or similar. Either. The standard flow rate is 1 or 2 g / sec.
-The system for recording measurements is installed. For this purpose, any system capable of recording measurement data from a scale and a height measuring device under time control can be used. Such systems include, for example, Windows® OS (XP or later), Microsoft Excel® (version 6 or later), a 4-port RS232 interface card, and a programmed VBA (Visual Basic for Application) module. It may consist of a computer equipped. The system must be able to retrieve all three measurements (σ1) to (σ3) within a time window of up to 0.5 seconds. Scales 1 and 2 and height measuring instrument 3 are connected to computer 12 (measurement value recording program conforms to appropriate settings (communication speed, parity, etc.) for scales 1 and 2 and height measuring instrument 3 It must be).

Measurement:
-The SAP sample to be analyzed must be well mixed. The recovered test material should not contain lumps or impurities.
- the SAP sample, using the weight 10 and the plunger 7, is turned by ^{21.0g / cm 2 ± 0.2g / cm} 2, placed in the notch of the supporting table 15. A tube (liquid feeding pipe 9) having an outflow end from the peristaltic pump is installed by protruding a length of 2 to 3 cm through the supply opening of the cover plate 8 of the test apparatus.
The height measuring device 3 is attached to a measuring rod in the center of the plunger 7 of the test device; During the 30 minute test period, the measurements are queried every 10 seconds and recorded for a specific time.
-Weigh the scales 1 and 2 and set the height measuring device 3 to zero.
-Initialize the system for recording measurements.
Immediately, but in some cases, start charging with the peristaltic pump 11 within 0.5 seconds after initialization of the system for measurement recording.
-At the end of the test period, the peristaltic pump 11 is switched off.

4). Rating (.sigma.1) Time (t) height in seconds _{(h t) mm, (σ2} ) Time (t) flow in seconds (Fl.th. _t) g, and (.sigma.3) Time (t) overflow amount in seconds ( Fl.ov. _t) g data sequences are used to calculate the) further numbers in the following (each time t. :
Vzu _t [g]: The amount of input liquid at time t.

V _t [cm ³ ]: gel amount at time t (base area of measurement pot 6 = 28.27
cm ² ).

ΔV _t [cm ³ ]: Increased gel amount within 10 seconds at time t (base area of measurement pot 6 = 28.27 cm ² ).

QI _t : swelling index at time t (dimensionless) (E = SAP start weight g, 0.9
% NaCl solution is considered 1 cm ³ = 1 g).

Fl.th. _t [g / sec]: Average flow rate over 10 seconds at time t

Vu _t [g]: Amount of suspended matter in the APC measurement pot.

_{h (Vu) t [mm]} : theoretical for APC in the measurement pot (was calculated) of the liquid height (considering the area of the plunger = 5 cm ^2, the effective area = 28.27cm ² -5cm ² = 23. 27 cm ² ).

PI _t : Time t = 20 seconds... Transmission index at 120 seconds (dimensionless).

APC _i × ₁₀ seconds: APC _i × ₁₀ seconds value at time T = 20 seconds... 120 seconds (i = 2 to 12). Each of the above numbers is further used to measure the APC _max value (ie, the maximum of 11 measured APC values), the APC mean APC _mean , and the _sum of all APC values (APC _sum ).

Comparative example (not subject to the present invention)
Into an aqueous solution of 1972.90 g sodium acrylate having a neutralization degree of 70 mol% (based on acrylic acid) and a total monomer concentration of 39.37%, 1.170 g of polyethylene glycol 300 diacrylate (acrylic) as a crosslinking agent. Acid / ester component = 0.2% for 72%) and 2.560 g of polyethylene glycol 440 monoallyl ether acrylate (acrylic acid / ester component = 0.4% for 100%) are dissolved. The monomer solution is purged with nitrogen for 30 minutes in a plastic polymerization vessel to remove dissolved oxygen. At a temperature of 4 ° C., 0.6 g of sodium peroxodisulfate diluted with 10 g of distilled water, 0.14 g of 35% hydrogen peroxide solution diluted with 10 g of distilled water, and 0.24 diluted with 2 g of distilled water. Polymerization begins with a continuous charge of 03 g ascorbic acid. Once the final temperature (about 100 ° C.) has been reached, the gel is crushed with a meat grinder and dried at 150 ° C. for 2 hours in an air circulating drying shelf. The dried product is crushed to a coarse grind, crushed and sieved to fragments of 150-710 μm particle size. The resulting bulk is screened into pieces by particle size and mixed together to form the following PSD produced by synthesis.
> 150 μm = 15%
> 300μm = 48%
> 500 μm = 32%
> 600 μm = 5%
The intermediate thus obtained is based on 100 g of the intermediate and is coated with a solution of ethylene carbonate: water: aluminum butyrate: aluminum sulfate in a ratio of 1: 3: 0.4: 0.3%. And then post-heated in a drying shelf at 170 ° C. for 90 minutes.

(Subject of the present invention)
To an aqueous solution of 963.60 g of sodium acrylate having a neutralization degree of 70 mol% (based on acrylic acid) and a total monomer concentration of 40.30%, 0.775 g of polyethylene glycol 300 diacrylate (acrylic acid / ester component) = 0.20% for 83%) and 1.639 g of polyethylene glycol 440 monoallyl ether acrylate (acrylic acid / ester component = 0.40% for 78%) are dissolved. This solution is then mixed with 9.6 g of a 10% aqueous solution of Purliol A23R (BASF) comonomer, which is purged with nitrogen for 30 minutes in a plastic polymerization vessel to remove dissolved oxygen. . At a temperature of 4 ° C., 2 g of slightly calcined sodium carbonate was added as a blowing agent, 0.3 g of sodium peroxodisulfate diluted with 10 g of distilled water, 35% peroxidation diluted with 10 g of distilled water Polymerization begins with a continuous charge of 0.07 g of hydrogen water and 0.015 g of ascorbic acid diluted with 2 g of distilled water. Once the final temperature (about 100 ° C.) has been reached, the gel is crushed with a meat grinder and dried at 150 ° C. for 2 hours in an air circulating drying shelf. The dried product is crushed, crushed and sieved to coarse grinds to fragments of 150-710 μm particle size. The resulting bulk is screened into pieces by particle size and mixed together to form the following PSD produced by synthesis.
> 150 μm = 15%
> 300μm = 48%
> 500 μm = 32%
> 600 μm = 5%
The intermediate thus obtained is based on 100 g of the intermediate and is coated with a solution of ethylene carbonate: water: aluminum butyrate: aluminum sulfate in a ratio of 1: 3: 0.4: 0.3%. And then post-heated in a drying shelf at 170 ° C. for 90 minutes.

(Subject of the present invention)
To an aqueous solution of 1962.4 g of sodium acrylate having a neutralization degree of 70 mol% (based on acrylic acid) and a total monomer concentration of 39.6% by mass, 1.529 g of polyethylene glycol 300 diacrylate (ester component = 83 0.7%, 0.2% by weight with respect to acrylic acid) and 1.639 g of polyethylene glycol 440 monoallyl ether acrylate (acrylic acid / ester component = 0.40% with respect to 77.5%) are dissolved. . Thereafter, 10.0 g of sodium carbonate produced in a moving bed spray granulation process and having a particle size of 400 to 600 μm is added as a blowing agent (0.2% by mass with respect to the batch size). The monomer solution is purged with nitrogen for 15-30 minutes to remove dissolved oxygen. The monomer solution mixed with 0.6 g of sodium peroxodisulfate diluted with 10 g of distilled water and 0.14 g of 35% hydrogen peroxide diluted with 10 g of distilled water at a temperature of 20 ° C. Under noble gas and shaft shaking, it is transferred into a CRP 2.5 batch kneader manufactured by Wrist. The target set value during the reaction in the batch operation type kneading reactor and / or the peripheral device of the twin shaft and the same speed rotation, and thus the required parameter are the temperature of the oil in the heating circuit of the outer shell of the kneading reactor. Is 75 ° C. and the shaft speed is 60 revolutions per minute. After the monomer solution is transferred into the kneading reactor, the sodium carbonate is charged. After stirring for 30 seconds, 0.030 g of ascorbic acid diluted with 2 g of distilled water is charged into the kneading reactor and an exothermic reaction starts. The target value of oil in the heating circuit of the outer shell of the kneading reactor is set to 100 ° C. After 5 minutes, the heating circuit is switched off, the kneading reactor is opened, and the formed hydrogel is removed and dried in an air circulating drying cabinet at 150 ° C. for 2 hours. The dried product is crushed, crushed with a Lecce laboratory pulverizer and a cutting sprocket with a hole size of 2 mm, sifted into pieces by particle size, and the particle size distribution is as follows: To be mixed together.
> 150 μm = 15%
> 300μm = 48%
> 500 μm = 32%
> 600 μm = 5%
Post-crosslinking is based on 100 g of intermediate, coating a solution of ethylene carbonate: water: aluminum butyrate: aluminum sulfate in a ratio of 1: 3: 0.4: 0.3% and then in the drying shelf It is brought about by post-heating at 175 ° C. for 90 minutes. After a total of 10 minutes, the shaft rotating at the same speed stops.

The polymers obtained in the Comparative Examples and Examples 1 and 2 are measured for APC _max and APC _SUM values using the test methods described herein. Table 3 shows the results. As far as the APC analysis of the polymer according to the comparative example is concerned, the measurement values obtained continuously for 120 seconds in the measurement of the APC parameters and the measurement data derived purely in the series are exemplified in Tables 1 and 2. Has been edited.

Directly obtained measurements (σ1), (σ2) and (σ3)

Measured amount obtained from the measured values in Table 1 in an arithmetic series

Comparative example and APC parameters of the polymers according to Examples 1 and 2

  The polymer obtained in the comparative example and in Examples 1 and 2 is used for the production of the absorbent core according to the invention.

Non-woven fabric (Freudenberg material number 0287710) cut to a size of 12 × 12 cm is a twist nozzle having a standard diameter of 1.5 mm using a pneumatic hot melt glue gun manufactured by Bünen with an HB710 type sprayer. In the set, the adhesive (Dispomelt® CS22 from Henkel) is sprayed uniformly by a 30 second operation at 4 bar pressure. The spray gun is pre-adjusted to a melting temperature of 160 ° C. Exactly 5 g of SAP is evenly spread over a 10 × 10 cm pre-marked / central area. Another non-woven fabric of the same size is sprayed with adhesive as well, then
Nonwoven fabric Adhesive SAP
Adhesive To obtain an absorbent core with a layer sequence of nonwoven, it is placed on the SAP with the adhesive side facing down.

  Thereafter, each layer is compressed using a hand roller. The absorbent core is then stored for one hour to dry the adhesive before the core is measured.

  In order to measure the absorbent properties of the absorbent core, the core to be tested is weighed and has a 9 × 9 mm size (wire thickness 1.5 mm) mesh and a 12 × 12 cm size outer part. Placed on a wire mesh, the wire mesh is placed in a Petri dish using four approximately 1.2 cm high metal legs located at each corner of the wire mesh. The absorbent core is loaded with 200 g using a test plate (10 × 10 cm). This test plate is provided with a feeding tube having a height of 20 cm and an inner diameter of 20 mm in the center. This input tube may be used for test fluid to pass through the test plate and onto the absorbent core. Meanwhile, the absorbent core is under pressure of the test plate.

  A 0.9% NaCl solution slightly stained with 25 g of acid fuchsin at a time is continuously fed into the charging tube 4 times (delay time between each charging: 15 minutes). The absorbent core is weighed before the first charge (w1). The test solution is introduced via the input tube at each input. In the fully absorbed state of liquid (4 × 25 g = 100 g), the absorbent core is reweighed (w2). The amount of leakage (l) may be obtained in a differential series by the difference between the amount of liquid w0 charged and the weight difference between the absorbent cores before and after absorption (l = w0− (w1− w2)).

  The following measurement results are obtained.

The leak value of the polymer according to the comparative example and examples 1 and 2 in the absorbent core of the invention

Claims (15)

A method for producing absorbent polymer material particles having at least one of the following characteristics:
1) For at least one numerical value i selected from integers from 2 to 12,
The maximum APC _{i × 10 sec} value (= APC _max value) is 1.6 or more,
2) The total of all APC _{i × 10 sec} values (= APC _SUM ) is 12 or more for all the numerical values i in the integers from 2 to 12.
here,
The QI _{i × 10 sec} value is the numerical value of the swelling index determined by the test method described herein i × 10 sec after addition of a 0.9% strength by weight NaCl solution,
-PI _{i x 10 sec} value is the penetration index determined by the test method described herein i x 10 seconds after adding a 0.9% weight concentration NaCl solution,
Then,
The APC _{i × 10 sec} value is defined as follows:
APC _{i × 10 sec} = QI _{i × 10 sec} value ² × PI _{i × 10 sec} value
i) a polymerizable monoethylenically unsaturated acid functional monomer ([alpha] 1) or a salt thereof, and the polymerizable monoethylenically unsaturated acid functional monomer ([alpha] 1) and polymerizable mode Noechiren unsaturated monomers ([alpha] 2), foam Free polymerizing an aqueous monomer solution containing an agent (α3) and at least one crosslinking agent (α4) to obtain a hydrogel having a microporous structure;
ii) optionally crushing the hydrogel having a microporous structure;
iii) drying the hydrogel having a microporous structure, optionally ground, to obtain absorbent polymer material particles having a microporous structure;
iv) optionally crushing and sieving the absorbent polymer material particles having the resulting microporous structure;
v) A post-crosslinking is performed on the surface of the absorbent polymer material particles having a generated microporous structure together with a crosslinking agent having two or more functional groups capable of reacting with acidic groups on the surface of the polymer material particles, Bringing the surface of the polymer material particles into contact with the aluminum salt before post-crosslinking, during post-crosslinking or after post-crosslinking;
Have
The chemical structure of the monoethylenically unsaturated monomer (α2) is:
, And the at least one of ^{R 1} and ^{R 2} is allyl, when any one of ^{R 1} and ^{R 2} is allyl, or the other is methyl, ethyl of ^{R 1} and ^{R 2,} n-propyl, isopropyl , n-butyl, isobutyl, n- pentyl, 2-methylbutyl, 2,2-dimethylpropyl, a hydroxyl group or acetyl Le,, n are those taken from 2 to 20, m is from 2 to 20, EO and PO Are hydrophilic and hydrophobic blocks, respectively, to create surfactant properties,
A method for producing absorbent polymer material particles, wherein: The absorbent polymer material particles have a maximum APC _{i × 10 sec} value of 1.6 or more with respect to at least one numerical value i of integers 1) 2 to 12,
The manufacturing method of the absorptive polymer raw material particle of Claim 1 which has the characteristics of these. The absorbent polymer material particles have a maximum APC _{i × 10 sec} value of 2.0 or more for at least one numerical value i of integers 1) 2 to 12,
The manufacturing method of the absorptive polymer raw material particle | grains of Claim 2 which has the characteristics of these. The absorbent polymer material particles have 1) a maximum APC _{i × 10 sec} value of 2.4 or more for at least one numerical value i of integers from 2 to 12.
The manufacturing method of the absorptive polymer raw material particle of Claim 3 which has the characteristics of these. The total number of all APC _{i × 10 sec} values is 12 or more with respect to all the numerical values i in the integer from 2 to 12 for the absorbent polymer material particles 2),
The manufacturing method of the absorbent polymer raw material particle of any one of Claims 1-4 which has the characteristics of these. The total number of all APC _{i × 10 sec} values is 18 or more for all the numerical values i in the integer from 2 to 12 for the absorbent polymer material particles 2),
The manufacturing method of the absorptive polymer raw material particle of Claim 5 which has the characteristics of these. The total number of all APC _{i × 10 sec} values is 24 or more for all the numerical values i in the integer from 2 to 12 for the absorbent polymer material particles 2),
The manufacturing method of the absorptive polymer raw material particle | grains of Claim 6 which has the characteristics of these. An upper substrate layer; a lower substrate layer; and an absorbent layer disposed between the upper substrate layer and the lower substrate layer, wherein the absorbent layer comprises absorbent polymer material particles and the absorbent polymer material. A method for producing an absorbent core comprising less than 0.1 g cellulose fiber per gram of particles,
A) preparing the absorbent polymer material particles produced by the method for producing absorbent polymer material particles according to any one of claims 1 to 7;
B) incorporating the absorbent polymer material particles into an absorbent core;
The manufacturing method of an absorptive core characterized by comprising. The method for producing an absorbent core according to claim 8, wherein cellulose fibers are basically not used. 10. The method of manufacturing an absorbent core according to claim 8, wherein the absorbent core includes a thermoplastic material and various chambers that accommodate the absorbent polymer material particles. 11. The absorbent core includes layers of thermoplastic material and various chambers that contain the absorbent polymer material particles;
Each of the chambers is surrounded by an upper or lower substrate layer and also by a thermoplastic material;
The manufacturing method of the absorptive core of Claim 10 characterized by the above-mentioned. The absorbent core includes a first sublayer and a second sublayer adjacent to the first sublayer;
The first sub-layer also includes a chamber containing the absorbent polymer material particles surrounded by the upper substrate layer and the upper substrate layer and a first layer of thermoplastic material;
The second sublayer also includes a chamber containing the absorbent polymer material particles surrounded by the lower substrate layer and the lower substrate layer and a second layer of thermoplastic material;
The first layer of thermoplastic material is adjacent to the second layer of thermoplastic material;
The manufacturing method of the absorptive core of Claim 11 characterized by the above-mentioned. The method for producing an absorbent core according to any one of claims 8 to 12, wherein the layer of the thermoplastic material is obtained by melting thermoplastic fibers. It is a manufacturing method of a hygiene article, Comprising: The said hygiene article is provided with the absorptive core of any one of Claims 8-13, The manufacturing method of the hygiene article characterized by the above-mentioned. The method for manufacturing a sanitary article according to claim 14, wherein the sanitary article is a diaper.